Eighteen-year-old Daoist master Zhang Chen possesses an extremely high seniority, entrusted by elder Su Yaozu to protect his granddaughter Su Yuyan, who bears the Nine-Yin Cold Constitution. Su Yuyan is persecuted by her family elders and the Tang family in joint collusion, with her mother held hostage and their ancestral secret heavenly medicine recipe coveted. Zhang Chen steps in to sweep across various ancient martial arts masters and dismantle the monopoly of the pharmaceutical alliance, improving affordable life-saving heavenly medicines and resolving crises from multiple enemies. To neutralize his own natal pure-yang fire poison, he needs to utilize the power of the Nine-Yin constitution, along the way getting to know multiple women afflicted with cold poisons. While protecting Su Yuyan and her mother, he practices medicine to save the world, clears out evil forces in the business and martial arts worlds, and embarks on a path of cultivation and saving people.